Field of the Invention
The invention relates to a light emitting module, and relates particularly to a light emitting module having a light emitting diode.
Description of Related Art
With the evolution of photoelectrical technology, traditional incandescent bulbs and fluorescent lamps have been gradually replaced by light emitting diodes (LEDs). The light emitting diode has advantages such as long lifespan, small size, high shock resistance, high light efficiency and low power consumption. Therefore, the light emitting diode has been widely adopted in various types of different lighting applications.
However, at the current stage, the light emitting diode still faces many technical challenges, wherein an efficiency drop of the light emitting diode is one challenge thereof. More specifically, an operation range of the light emitting diode at a low current density corresponds to a peak of an external quantum efficiency. However, the external quantum efficiency decreases along with the increase in the current density of the light emitting diode. This phenomenon namely is the efficiency droop effect of the light emitting diode.
Generally speaking, the current density of the light emitting diode is typically at a high current density operation range in order to make the light emitting diode achieve a high light emitting brightness. Due to the aforementioned efficiency droop effect, the external quantum efficiency of the light emitting diode under the high current density operation range is limited and the luminous efficiency of the light emitting diode cannot be further enhanced. Therefore, how to achieve an ideal luminous efficiency for the light emitting diode under operation conditions of different current densities is a problem needing to be solved by researchers.